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Incisive canal cysts
INCISIVE M.
MICHAEL
CANAL
COIIFX,
D.M.D.,
CYSTS BOSTON,
Mass.
I
NC~ISIVE canal cysts were first described in 3914 by Meyer, who, in 1931, Other imreported a more compld-e study- based on dissected specimens. portant contribnt,ions to t,hc clinical and histopathologic studies of incisive canal cysts were made by R’ydzek (1923)) Rawengel (1923), Kronfeld (1928)) Schroff (1929-1930)) Noyes (1935), Stafne, Austin, and Gardner (1936)) and Thoma (1941). R\-dzek (1923) demonstrated that in the human fetus wide communications csist between the oral and nasal cavities after fusion of the palatine processes of the maxilla. These arc the nasopalatine ducts which in certain animals (dogs, rabbits, and monkeys) persist through life. In humans, however, these ducts usually become obliterated in the first year of life. When they occasionally persist, they pass from the nasal to the oral cavity, and open as two small slits in the mouth on each side of the papilla palatina. Rawengel (1923) made serial sections on twentyseven human necropsies, nineteen newborn, and tight adults. His findings were as follows: in five of the newborns, he found a passage from the nasal to oral cavity; in three adult cases, no openin, (1 at all; fourteen showed a blind sac from the nasal side; and in four cases, a blind sac from the mouth. His studies also demonstrated that there are various types of epithelium in the incisive canal which may give rise may be derived from the nasopalatine ducts or their to cysts. Epithelium remnants, or from cpithelial cell r&s which become enclosed when the median primary and two lateral plates unite during embryonic development. These cell rests may be stimulated and give rise to cysts in later life. Noyes (1936) found the nasopalatine duct and canal when he made serial He was not able to demonstrate any comrnunicasections in newborn infants. tion between the oral and nasal cavity in his studies. Burket (193i) made studies on thirty-five human necropsies, ages ranging and found portions of the rudimentary from thirty-two to seventy-three, nasopalatine duct or cystic structures in twenty-one of the cases. Thoma in 1941, while workinp on autopsy material collected in the Department of Oral Pathology, IIarrard Dental School, demonstrated an incisive canal cyst radiographically in the anterior port,ion of an excised maxilla. This specimen was cut in an oblique frontal section, for histopathologic studies, and showed an incisive canal cyst consistin, e of a connective tissue sac which was lined with epithelium. ETIOLOGIC
fitting
FACTORS
Trauma of the papilla palatina due to irritation during mastication, illdentures, or mouth infection may cause occlusion of the openings of the prom
the
Dental
Clinic
of the
Beth
Israel
Hospital. 670
Incisive
671
Canal Cysts
nasopalatine ducts, thereby causin g cysts by retention of the secretion the mucous glands which are located in the incisive canal. DIAGSOSIS
OF
INCISIVE
CANAL
from
CYSTS
Incisive canal cysts can be differentiated first from median cysts, which may occur anywhere within the median suture of the palatine bones anterior or posterior to the incisive canal region, and second from cysts of the palatine papilla which do not show on the roentgenogram. Incisive canal cysts occur in either dentulous or edentulous mouths and are not of odontogenic origin. They may or may not give rise to clinical symptoms. Occasionally the patient may complain of a salty or disagreeable taste which occurs when the cyst is infected. Later, the palatine papilla may swell and pressure on this area may cause pus to exude. In most cases, pain is absent, but when it does occur, it is of a reflex type manifesting itself on the bridge and side of the nose, and over the eyes. There may also be vague pain in the anterior portion of the maxilla. The x-ray is necessary for the diagnosis of incisive canal cysts. Stafne et al. point out that its image is not al\vays constant, but that the majority of these cysts are situated in the midline extending laterally in a symmetrical manner. When the cyst extends to ouly one side of the median line, its origin is probably from a single nasopalatinc duct. In rare instances, one may find on the roentgenogram a heart-shaped area which is a double cyst caused by involvement of both nasopalatine ducts. The incisive canal cyst should be differentiated also from the radicular cyst. This is often difficult, because the apices of the incisor teeth in the srnall intraoral film seem to protrude into the cystic area. A mistaken diagnosis may lead to unnecessary devitalization or loss of incisor teeth. When an incisive canal cyst, is suspected, a large intraoral film should be used; a pnlp tester also will aid in establishing the diagnosis. In the edentulous jaw, this cyst appears nearer the alveolar border than in the dentulons one. This is not caused by a change in the location of the cyst, but by resorption of the alveolar process after the teeth are lost. Incisive canal cyst,s, like odontogenic cysts, arc surrounded by a layer of cortical bone which produces radiographically the light line around the cystic area. In the edentulous jaw, these cysts can enlarge to considerable size as in the case reported by Dr. Levine and me in 1936 and also by Worth in 1939. HISTOPATHOLOGT
OF
ISCISIVE
CASAL
CYST
The histopathology of the incisive canal cyst is of interest. The cyst wall is composed of a thick membrane of connective tissue, and in it may be found groups of I~L~O~R glands and accessory cysts with mucoid contents as described by Stafne et al. The epithelial lining of the lumen varies, being either squamous, transitional, or ciliated columnar epithelium. Squamous or transitional epithelium is found in cysts arising near the oral part of the incisive canal; ciliated columnar cpithelium is found in cysts derived from a cord extending down from the nasal cavity.
672
211. Nichael CASE
Cohen
REPORT
S. B., a 53-year-old Jewish cantor, with a past medical history of nephrolithiasis and renal glycosuria, complained of a very disagreeable taste in the mouth, which at times was accompanied by a puslike exudate, the source of which he did not know. Local Examination.-Oral examination presented an unclean mouth, with a marked gingivitis and considerable serumal calculus on the teeth. There were, however, no suppurative periodontal pockets. The mucosa in the region of the incisive canal appeared red and slightly swollen, and digital pressure on this area caused a foul-smelling pus to exude. A provisional diagnosis of an infected incisive canal cyst was made.
Fig.
l.-Intraoral
Fig.
2.-Large
roentgenograms protrusion of
intraoral
x-ray
showing large right maxillary
showing
an
infected
cyst in the incisor root
incisive
incisive canal region into cystic area.
canal
cyst
of
with
nonodontogenic
apparent
origin.
Roentgen Examination.-X-ray examination of the mouth by intraoral films showed several carious teeth and a cystic area in the region of the incisive canal (Fig. 1). The maxillary right central incisor root appeared to extend into the cystic cavity. Pulp and thermal tests indicated that the tooth was vital. A large intraoral roentgenogram (Fig. 2) showed a cyst in the midline of the incisive canal region, but the outline of the cystic cavity on the posterior right border was not clear, suggesting evidence of bone pathology due to the suppurative cystic contents.
Incisive
673
Canal Cysts
The anatomic location of the cystic area, plus its outline, substantiated the impression that this was an infected incisive canal of nonodontogenic origin. Operation.-Under procaine anesthesia, the gingiva of the maxillary incisors was separated interproximally so that the lingual mucoperiosteum could be elevated to expose the palaial bone and give access to the incisive canal (Fig. 3).
Fig.
Fig.
I.-Low
power
3.-Incisive
photomicrograph
canal
of
cyst
after
wall
removal
showing
of
cyst.
bundles
of
collagen
fibers.
The cyst could be readily seen in the ineisive canal and was completely enucleated. The mucoperiosteum was then replaced, and the lingual papilla was sutured interproximally to the labial gingiva. Since healing was uneventful, the sutures were removed within five days.
674
11. Michael
Cohen
Pathologic Exanzination.-The specimen consisted of several pieces of tissue which were preserved in formalin. Sections were made and stained with hematoxylin and eosin. Microscopic examination showed a fibrous connective Gssue sac, composed of collagen fiber bundles, and lined with ciliated columnar epithelium. This microscopic appearance was consistent wit,h that of incisive canal cysts arising from the nasal portion of the nasopalatine ducts or its remnants, as shown in Figs. 4 and 5.
Fig.
5.-High
power
photomicrograph lumen
showing ciliated columnar of the cyst sac was line&
epithelium
with
which
the
CONCLUSION
This case demonstrates the importance of utilizing clinical roentgenographic and microscopic aids to obtain an accurate diagnosis in cases of incisive canal cysts. REFERENCES Bauer,
TV. : Ueber Zysten im Weiehgewebe des Ductus Nasopalatinus, Ztschr. f. Stomatol. 28: 481, 1930. and Peculiar Bony Pattern Observed in Burket, L. W.: Nasopalatine Duct Structures Anterior Maxillary Region, Arch, Path. 23: 703, 1937. Cohen, M. Michael, and Levine, J.: Incisive Canal Cyst of Edentulous Maxilla, INT. J. ORTHODONTIA 22: 526, 1936. Congdon, E. D.: Supernumerary Paranasal Sinus, Anat. Rec. 19: 367, 1920. Epithelial Rests in the Region of the Palatinal Papilla of the Upper Jaw, J. Dent. Grohs, R.: Research 14: 187, 1934. Hyde, W. H.: Incisive Canal Cysts, Anr. J. ORTHODONTICS ANU ORAL S,TTRG. 24: 1093, 1938. Kronfeld, R. : Rimtgenologisch-Histologische Untersuchung einer Medianen Oberkieferzyste, Korr. f. ZahnLrzte 52: 366, 1928. Spolia Anatomica: Unique Supernumerary Para-Nasal Sinus Directly Meyer, A. W.: Above Superior Incisors, J. Anat. and Physiol. 48: 118, 1914. Idem: Our Inadequate Terminology Concerning the Anterior Palatine Region, Anat. Rec. 49: 19, 1931. Idem : Median Anterior Maxillary Cysts, J. A. D. A. 18: 1851, 1931.
Anatomy of Frenum Labii in New Born Infants, Angle Orthodontist 5: 3, 1935. F. B.: K.: Die Entwicklung der Nasengaumenstrange und anderer Epithelziige im vorderen Teil des Mensehlichen Gaumens, Arch. f. mikr. Anat,. 97: 523, 1923. und andere Epitheliale Gehilde im Vorderen Teile des Rawengel, G. : Die Nasengxumengange Gaumens hei Neugeborenen und Erwachsenen. Arch. f. mikr. Anat. 97: 507, 1923. Rushton, M. A.: A Cyst in the Median Palatine Suture, British Dent. J. 51: 109, 1930. Rydzek, A.: Ueber den vorderen Gaumenschluss heim Menschen Arch. f. mikr. Anat. 97: 486, 1923. Rchroff, J. : Unusual Cysts in the Maxilla: Cysts of Nasopalatine Duct and Fissural Cysts, Dent. Items Interest 51: 109, 1929. Silva, C. A.: Facial Cleft or Fissural Cyst, Ax J. ORTIIODONTI~S AND ORAL SURG. 24: 801, 1938 Stafne, E. C.,’ Austin, L. T., and Gardner, B. 8.: Median Anterior Maxillary Cysts, J. ,4. D. A. 23: 801. 1936. Thoma, K. H.: ‘Oral Pathology, C. V. Mosby Co., 1941, p. 877. Incisive Canal Cvst, A&x. J. ORTHODONTICS AND ORAL SURG. 27: Idem : Case Report No. 48. 226, 1941. Beitrag ZUT Histologie der Gegend seitlich von der Papilla palatina, Wermuth, H.: Deutsch. Monatschr. Zahnheilk. Heft 5, 8. 203, 1927. Wild, H. A. P.: Cysts in Region of Nasopalatine Duct, Dent. Items Interest 52: 63, 1930. Worth, H. M.: Radiologic Findings in Some Less Common Jaw Affections, Proc. Royal Sot. Med. 32: 331 (Section of Odontology, pp. T-19), 1939. Noyes, Peter,
520
BEAVOX
STNEET
MICHAEL
CANAL
COIIFX,
D.M.D.,
CYSTS BOSTON,
Mass.
I
NC~ISIVE canal cysts were first described in 3914 by Meyer, who, in 1931, Other imreported a more compld-e study- based on dissected specimens. portant contribnt,ions to t,hc clinical and histopathologic studies of incisive canal cysts were made by R’ydzek (1923)) Rawengel (1923), Kronfeld (1928)) Schroff (1929-1930)) Noyes (1935), Stafne, Austin, and Gardner (1936)) and Thoma (1941). R\-dzek (1923) demonstrated that in the human fetus wide communications csist between the oral and nasal cavities after fusion of the palatine processes of the maxilla. These arc the nasopalatine ducts which in certain animals (dogs, rabbits, and monkeys) persist through life. In humans, however, these ducts usually become obliterated in the first year of life. When they occasionally persist, they pass from the nasal to the oral cavity, and open as two small slits in the mouth on each side of the papilla palatina. Rawengel (1923) made serial sections on twentyseven human necropsies, nineteen newborn, and tight adults. His findings were as follows: in five of the newborns, he found a passage from the nasal to oral cavity; in three adult cases, no openin, (1 at all; fourteen showed a blind sac from the nasal side; and in four cases, a blind sac from the mouth. His studies also demonstrated that there are various types of epithelium in the incisive canal which may give rise may be derived from the nasopalatine ducts or their to cysts. Epithelium remnants, or from cpithelial cell r&s which become enclosed when the median primary and two lateral plates unite during embryonic development. These cell rests may be stimulated and give rise to cysts in later life. Noyes (1936) found the nasopalatine duct and canal when he made serial He was not able to demonstrate any comrnunicasections in newborn infants. tion between the oral and nasal cavity in his studies. Burket (193i) made studies on thirty-five human necropsies, ages ranging and found portions of the rudimentary from thirty-two to seventy-three, nasopalatine duct or cystic structures in twenty-one of the cases. Thoma in 1941, while workinp on autopsy material collected in the Department of Oral Pathology, IIarrard Dental School, demonstrated an incisive canal cyst radiographically in the anterior port,ion of an excised maxilla. This specimen was cut in an oblique frontal section, for histopathologic studies, and showed an incisive canal cyst consistin, e of a connective tissue sac which was lined with epithelium. ETIOLOGIC
fitting
FACTORS
Trauma of the papilla palatina due to irritation during mastication, illdentures, or mouth infection may cause occlusion of the openings of the prom
the
Dental
Clinic
of the
Beth
Israel
Hospital. 670
Incisive
671
Canal Cysts
nasopalatine ducts, thereby causin g cysts by retention of the secretion the mucous glands which are located in the incisive canal. DIAGSOSIS
OF
INCISIVE
CANAL
from
CYSTS
Incisive canal cysts can be differentiated first from median cysts, which may occur anywhere within the median suture of the palatine bones anterior or posterior to the incisive canal region, and second from cysts of the palatine papilla which do not show on the roentgenogram. Incisive canal cysts occur in either dentulous or edentulous mouths and are not of odontogenic origin. They may or may not give rise to clinical symptoms. Occasionally the patient may complain of a salty or disagreeable taste which occurs when the cyst is infected. Later, the palatine papilla may swell and pressure on this area may cause pus to exude. In most cases, pain is absent, but when it does occur, it is of a reflex type manifesting itself on the bridge and side of the nose, and over the eyes. There may also be vague pain in the anterior portion of the maxilla. The x-ray is necessary for the diagnosis of incisive canal cysts. Stafne et al. point out that its image is not al\vays constant, but that the majority of these cysts are situated in the midline extending laterally in a symmetrical manner. When the cyst extends to ouly one side of the median line, its origin is probably from a single nasopalatinc duct. In rare instances, one may find on the roentgenogram a heart-shaped area which is a double cyst caused by involvement of both nasopalatine ducts. The incisive canal cyst should be differentiated also from the radicular cyst. This is often difficult, because the apices of the incisor teeth in the srnall intraoral film seem to protrude into the cystic area. A mistaken diagnosis may lead to unnecessary devitalization or loss of incisor teeth. When an incisive canal cyst, is suspected, a large intraoral film should be used; a pnlp tester also will aid in establishing the diagnosis. In the edentulous jaw, this cyst appears nearer the alveolar border than in the dentulons one. This is not caused by a change in the location of the cyst, but by resorption of the alveolar process after the teeth are lost. Incisive canal cyst,s, like odontogenic cysts, arc surrounded by a layer of cortical bone which produces radiographically the light line around the cystic area. In the edentulous jaw, these cysts can enlarge to considerable size as in the case reported by Dr. Levine and me in 1936 and also by Worth in 1939. HISTOPATHOLOGT
OF
ISCISIVE
CASAL
CYST
The histopathology of the incisive canal cyst is of interest. The cyst wall is composed of a thick membrane of connective tissue, and in it may be found groups of I~L~O~R glands and accessory cysts with mucoid contents as described by Stafne et al. The epithelial lining of the lumen varies, being either squamous, transitional, or ciliated columnar epithelium. Squamous or transitional epithelium is found in cysts arising near the oral part of the incisive canal; ciliated columnar cpithelium is found in cysts derived from a cord extending down from the nasal cavity.
672
211. Nichael CASE
Cohen
REPORT
S. B., a 53-year-old Jewish cantor, with a past medical history of nephrolithiasis and renal glycosuria, complained of a very disagreeable taste in the mouth, which at times was accompanied by a puslike exudate, the source of which he did not know. Local Examination.-Oral examination presented an unclean mouth, with a marked gingivitis and considerable serumal calculus on the teeth. There were, however, no suppurative periodontal pockets. The mucosa in the region of the incisive canal appeared red and slightly swollen, and digital pressure on this area caused a foul-smelling pus to exude. A provisional diagnosis of an infected incisive canal cyst was made.
Fig.
l.-Intraoral
Fig.
2.-Large
roentgenograms protrusion of
intraoral
x-ray
showing large right maxillary
showing
an
infected
cyst in the incisor root
incisive
incisive canal region into cystic area.
canal
cyst
of
with
nonodontogenic
apparent
origin.
Roentgen Examination.-X-ray examination of the mouth by intraoral films showed several carious teeth and a cystic area in the region of the incisive canal (Fig. 1). The maxillary right central incisor root appeared to extend into the cystic cavity. Pulp and thermal tests indicated that the tooth was vital. A large intraoral roentgenogram (Fig. 2) showed a cyst in the midline of the incisive canal region, but the outline of the cystic cavity on the posterior right border was not clear, suggesting evidence of bone pathology due to the suppurative cystic contents.
Incisive
673
Canal Cysts
The anatomic location of the cystic area, plus its outline, substantiated the impression that this was an infected incisive canal of nonodontogenic origin. Operation.-Under procaine anesthesia, the gingiva of the maxillary incisors was separated interproximally so that the lingual mucoperiosteum could be elevated to expose the palaial bone and give access to the incisive canal (Fig. 3).
Fig.
Fig.
I.-Low
power
3.-Incisive
photomicrograph
canal
of
cyst
after
wall
removal
showing
of
cyst.
bundles
of
collagen
fibers.
The cyst could be readily seen in the ineisive canal and was completely enucleated. The mucoperiosteum was then replaced, and the lingual papilla was sutured interproximally to the labial gingiva. Since healing was uneventful, the sutures were removed within five days.
674
11. Michael
Cohen
Pathologic Exanzination.-The specimen consisted of several pieces of tissue which were preserved in formalin. Sections were made and stained with hematoxylin and eosin. Microscopic examination showed a fibrous connective Gssue sac, composed of collagen fiber bundles, and lined with ciliated columnar epithelium. This microscopic appearance was consistent wit,h that of incisive canal cysts arising from the nasal portion of the nasopalatine ducts or its remnants, as shown in Figs. 4 and 5.
Fig.
5.-High
power
photomicrograph lumen
showing ciliated columnar of the cyst sac was line&
epithelium
with
which
the
CONCLUSION
This case demonstrates the importance of utilizing clinical roentgenographic and microscopic aids to obtain an accurate diagnosis in cases of incisive canal cysts. REFERENCES Bauer,
TV. : Ueber Zysten im Weiehgewebe des Ductus Nasopalatinus, Ztschr. f. Stomatol. 28: 481, 1930. and Peculiar Bony Pattern Observed in Burket, L. W.: Nasopalatine Duct Structures Anterior Maxillary Region, Arch, Path. 23: 703, 1937. Cohen, M. Michael, and Levine, J.: Incisive Canal Cyst of Edentulous Maxilla, INT. J. ORTHODONTIA 22: 526, 1936. Congdon, E. D.: Supernumerary Paranasal Sinus, Anat. Rec. 19: 367, 1920. Epithelial Rests in the Region of the Palatinal Papilla of the Upper Jaw, J. Dent. Grohs, R.: Research 14: 187, 1934. Hyde, W. H.: Incisive Canal Cysts, Anr. J. ORTHODONTICS ANU ORAL S,TTRG. 24: 1093, 1938. Kronfeld, R. : Rimtgenologisch-Histologische Untersuchung einer Medianen Oberkieferzyste, Korr. f. ZahnLrzte 52: 366, 1928. Spolia Anatomica: Unique Supernumerary Para-Nasal Sinus Directly Meyer, A. W.: Above Superior Incisors, J. Anat. and Physiol. 48: 118, 1914. Idem: Our Inadequate Terminology Concerning the Anterior Palatine Region, Anat. Rec. 49: 19, 1931. Idem : Median Anterior Maxillary Cysts, J. A. D. A. 18: 1851, 1931.
Anatomy of Frenum Labii in New Born Infants, Angle Orthodontist 5: 3, 1935. F. B.: K.: Die Entwicklung der Nasengaumenstrange und anderer Epithelziige im vorderen Teil des Mensehlichen Gaumens, Arch. f. mikr. Anat,. 97: 523, 1923. und andere Epitheliale Gehilde im Vorderen Teile des Rawengel, G. : Die Nasengxumengange Gaumens hei Neugeborenen und Erwachsenen. Arch. f. mikr. Anat. 97: 507, 1923. Rushton, M. A.: A Cyst in the Median Palatine Suture, British Dent. J. 51: 109, 1930. Rydzek, A.: Ueber den vorderen Gaumenschluss heim Menschen Arch. f. mikr. Anat. 97: 486, 1923. Rchroff, J. : Unusual Cysts in the Maxilla: Cysts of Nasopalatine Duct and Fissural Cysts, Dent. Items Interest 51: 109, 1929. Silva, C. A.: Facial Cleft or Fissural Cyst, Ax J. ORTIIODONTI~S AND ORAL SURG. 24: 801, 1938 Stafne, E. C.,’ Austin, L. T., and Gardner, B. 8.: Median Anterior Maxillary Cysts, J. ,4. D. A. 23: 801. 1936. Thoma, K. H.: ‘Oral Pathology, C. V. Mosby Co., 1941, p. 877. Incisive Canal Cvst, A&x. J. ORTHODONTICS AND ORAL SURG. 27: Idem : Case Report No. 48. 226, 1941. Beitrag ZUT Histologie der Gegend seitlich von der Papilla palatina, Wermuth, H.: Deutsch. Monatschr. Zahnheilk. Heft 5, 8. 203, 1927. Wild, H. A. P.: Cysts in Region of Nasopalatine Duct, Dent. Items Interest 52: 63, 1930. Worth, H. M.: Radiologic Findings in Some Less Common Jaw Affections, Proc. Royal Sot. Med. 32: 331 (Section of Odontology, pp. T-19), 1939. Noyes, Peter,
520
BEAVOX
STNEET